<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div{
            color: red;
        }
        p{color: blue !important;}/*重要的，提高至最高优先级*/
        #p2{color: green}/*间接选中没有直接选中优先级高*/
    </style>
</head>
<body>
<p>p1</p>
<div>
    <p id="p2">p2</p>
    <span>span1</span>
    <a href="">超链接</a>
</div>
</body>
</html>